Placebos and painkillers: is mind as real as matter?

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Abstract

Considerable progress has been made in our understanding of the neurobiological mechanisms of the placebo effect, and most of our knowledge originates from the field of pain and analgesia. Today, the placebo effect represents a promising model that could allow us to shed new light on mind–body interactions. The mental events induced by placebo administration can activate mechanisms that are similar to those activated by drugs, which indicates a similarity between psychosocial and pharmacodynamic effects. These new neurobiological advances are already changing our conception of how clinical trials and medical practice must be viewed and conducted.

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Figure 1: An emerging uncertainty principle imposes limitations on our understanding of the effects of a therapeutic agent.
Figure 2: Putative cascade of biochemical events in the brain after placebo administration.
Figure 3: Summary of brain imaging studies showing the different brain regions that are involved in placebo analgesia.
Figure 4: Examples of two clinical trials that used the open–hidden paradigm, revealing an ineffective and an effective treatment.

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Acknowledgements

This work was supported by grants from the 'Neuroscience' project of the National Research Council, from the 'Alzheimer's disease' project of the Italian Ministry of Health, and from the Italian Ministry of University and Research (FIRB).

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Correspondence to Fabrizio Benedetti.

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Colloca, L., Benedetti, F. Placebos and painkillers: is mind as real as matter?. Nat Rev Neurosci 6, 545–552 (2005) doi:10.1038/nrn1705

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